Tenaris S.A.

Transaction in Own Shares • Aug 16, 2025

Giovanni Sardagna Tenaris 1-888-300-5432 www.tenaris.com

Weekly Report (August 11, 2025 – August 15, 2025) on the First Tranche of Tenaris Share Buyback Program.

Luxembourg, August 15, 2025. - Tenaris S.A. (NYSE and Mexico: TS and EXM Italy: TEN) ("Tenaris") announced today that pursuant to its First Tranche of the USD1.2 billion Share Buyback Program announced on June 6, 2025, covering up to USD 600 million to be executed in the open market, it has repurchased the following ordinary shares from August 11, 2025 to (and including) August 15, 2025:

Date	Trading Venue	Shares Purchased	Weighted Average Price (EUR)	Purchases in EUR	Reference FX	Purchases in USD
11-ago-25	MTAA	377,703	15.3313	5,790,678	1.1595	6,714,291
11-ago-25	CEUX	234,932	15.3333	3,602,283	1.1595	4,176,847
11-ago-25	TQEX	48,000	15.3392	736,282	1.1595	853,719
11-ago-25	AQEU	21,428	15.3368	328,637	1.1595	381,055
12-ago-25	MTAA	428,528	15.3966	6,597,874	1.1659	7,692,462
12-ago-25	CEUX	249,153	15.4030	3,837,704	1.1659	4,474,379
12-ago-25	TQEX	48,000	15.3631	737,429	1.1659	859,768
12-ago-25	AQEU	32,000	15.3673	491,754	1.1659	573,336
13-ago-25	MTAA	200,000	15.3549	3,070,980	1.1718	3,598,574
13-ago-25	CEUX	46,492	15.3569	713,973	1.1718	836,634
14-ago-25	MTAA	85,507	15.4268	1,319,099	1.1659	1,537,938
		1,771,743	15.3672	27,226,692		31,699,001

From August 11, 2025 to (and including) August 15, 2025, the Company has purchased a total of 1,771,743 ordinary shares for a total consideration of €27,226,692, equivalent to USD31,699,001.

As of August 15, 2025, the Company held in treasury 28,306,193 ordinary shares equal to 2.64% of the total issued share capital.

Tenaris intends to cancel treasury shares purchased under the Programs in due course.

Details of the above transactions, are available on Tenaris's corporate website under the Share Buyback Program Section https://ir.tenaris.com/share-buyback-program.

Some of the statements contained in this press release are "forward-looking statements". Forward-looking statements are based on management's current views and assumptions and involve known and unknown risks that could cause actual results, performance or events to differ materially from those expressed or

implied by those statements. These risks include but are not limited to risks arising from uncertainties as to future oil and gas prices and their impact on investment programs by oil and gas companies.

Tenaris is a leading global supplier of steel tubes and related services for the world's energy industry and certain other industrial applications.